Word list not working

I added a word to the list of words not to show. It took one word. Then after that it would take any more and the first word was back on the image. I am getting so frustrated with this whole site. I would like to recommend it for teachers to use, but it is just so unstable.

Hi Andrea! Did you click visualize after adding a word to the list? If yes it should not be displayed in your cloud. If it still does please save your cloud and provide its nubmer so I could investigate the root cause.